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#ObjectScript

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InterSystems ObjectScript is a scripting language to operate with data using any data model of InterSystems Data Platform (Objects, Relational, Key-Value, Document, Globals) and to develop business logic for serverside applications on InterSystems Data Platform.

Documentation.

Hello, we have a few hundreds of triggers to port from Oracle to Cachè for a migration project, and many of them have to change (for example, normalize a value, null it, etc) the value which is being inserted.

The documentation says "You cannot set {fieldname*N} in trigger code." , so we're unlucky.

Is there a good workaround for this ?

SqlComputeOnChange doesn't seem the best way, but I'm not totally sure: for example normalization and validation could have a better place somewhere else than a trigger.

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What are the differences between a process private global and a percent variable? Basically I have some code running in an Ensemble operation that processes requests, and it needs access to pieces of data that are scattered throughout XData blocks in various classes. Rather than opening the XData object and deserializing the XML on each request, I opted to cache this data in a percent variable, something like:

set %MyVar(sub1,sub2) = myValue

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Question
· Mar 29, 2017
Count Number of Pages?

Hello,

We are working on creating a metadata file to accompany PDF documents produced by one of our third party systems for ingestion into our DMS. One of the pieces of data that the metadata file must contain is the number of pages of the PDF document.

In Cache ObjectScript does anybody know if there is currently a way of counting the number of pages within a file (specifically a PDF) without invoking a non-Caché ObjectScript program/function from within Caché ObjectScript?

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Article
· Mar 28, 2017 2m read
Map, Reduce and Filter Collections

Inspired by the article "Declarative development in Caché" that's still trending on the dev com. The OP explored a functional style of iterating over a collection. A comment today suggested "Caché would need syntax support for anonymous functions".

With Macros you can kind of get anonymous like syntax using dot notation.

This is not production code, but it does work. First the macros...

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Let's say I have two classes: A and B. They share no common parent except %SystemBase. But these classes have some properties with the same name (type may be the same or not):

Class A {

Property data As C;

Property data2;

}
Class B {

Property data As D;

Property data3;

}

I need to automatically convert object of class A into object of class B. I'm planing to write a class generator that generates a separate class that converts A to B. It would work like this:

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Hi!

Consider I have a class Package.Data with Property UniqueStringValue as %String.

I introduced the Index for this property:

 Index ValueIndex on UniqueStringValue [Unique];

It works well. But if I try to check if there is an object with the certain value in code like this:

if ##class(Package.Data).ValueIndexExists(value)

this expression fails, if value="value", even if there is an instance with instance.UniqueStingValue="Value"

How can I set the index to prevent saving case sensitive values in this class?

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While I can see the benefits that $ZSTORAGE could have if used properly, I have not seen it used in the environments I have worked in. I was wondering if there are any developers that promote its usage.

If used properly, I would imagine it could be highly effective in maximizing free memory since some processes will never go over X amount, while others may very well need much more.

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If I were trying to access an index of a global variable, what time complexity would this operation have? My understanding of languages like Java/C++ is that arrays are stored as blocks of memory so that x[15] would have a lookup time complexity of O(1) because it just goes to (address of the array + 15) and retrieves the value stored there.

How does this work in Cache where the index of a variable isn't necessarily an integer value? If I were to have a variable like the following:

x("Adam") = "Red"

x("George") = "Blue"

x("Bryan") = "Green"

etc...

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I am in the planning stages of making things more uniform in our routines and I would like to know what the easiest way would be to include an .inc at the beginning of each .mac routine. Has anyone written something that would open all routines and place something into the first row while leaving the rest of the routine unchanged? Thanks for any guidance you all may provide.

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Points to remember before you start:

  1. It is not possible in a COS (Caché Object Script) job/process context to have multiple Named Pipes. It is a one Named Pipe per job/process limited line of communication.
  1. Named Pipes, in Caché, like most pipes on most operating systems are Unidirectional. That means you open them for either Read or Write, but not both.
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Hello guys,

I've got this piece of code which runs the method "WebMethod", that belongs to %SOAP.WebBase.cls.

It grabs the outcome from an internal webservice we have and after that, it writes into a file.

The thing is, when I browse the file contents, I realize that in the place where a special character should be, I see a question mark.

By querying the same webservice from a special soap tool called "SoapSonar" (I've been using this for years), the outcome shows up this special character (shows it properly).

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Article
· Jan 16, 2017 15m read
Part I – Thoughts about package manager

Have you ever thought what could be a reason why some development environment (database, language) would eventually become popular? What part of this popularity could be explain as language quality? What by new and idioms approaches introduced by early language adopters? What is due to healthy ecosystem collaboration? What is due to some marketing genius?

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So I know it's been a while, and I hate to let my adoring fans down... just not enough to actually start writing again. But the wait is over and I'm back! Now bask in my beautiful ginger words!

For this series, I am going to look at some common problems we see in the WRC and discuss some common solutions. Of course, even if you find a solution here, you are always welcome to call in and expression you gratitude, or just hear my voice!

This week's common problem: "My query returns no data."

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